A parallel flat-panel type plasma processing apparatus used in a semiconductor fabrication process is configured in such a manner that a substrate placing table serving as a lower electrode and an upper electrode are placed opposite to each other within a vacuum chamber, and high-frequency power is applied between both the electrodes to convert a processing gas into plasma. Since a gas supply unit is generally configured as a gas shower head that ejects processing gas in a shower type, the upper electrode is configured by an electrode plate positioned in a lowest part of the gas shower head.
In this apparatus, the temperature of a substrate is determined by heat dissipation to the placing table, heat absorption from plasma, and radiation heat from the upper electrode, but the temperature of the upper electrode is set to a temperature which is considered to be appropriate with respect to some processes. It is difficult to install a temperature detecting unit in the upper electrode and a neighboring region thereof because a high-frequency power flows on the upper electrode and the neighboring region thereof. As a result, for example, a value of power supplied to a heater for heating the upper electrodes, which is placed above the gas shower head, is set to an appropriate value in advance.
Meanwhile, as the plasma processing apparatus is actuated, a processing environment is changed. As a detailed example, in a plasma etching apparatus, a reaction product in etching may be adhered to a member. When the reaction product is adhered, several changes occur. For example, a change in a surface state of a ring member (a focus ring) for adjusting a state of plasma, which is placed to surround a substrate placing area in the placing table, a change in diameter of a gas supply hole of the gas shower head, and a change in state of an inner wall surface of the vacuum chamber occur, such that a processing result or a processing speed is changed. Further, according to a verification test of the present inventors, the upper electrode is exposed to plasma, and as a result, a plate thickness may decrease.
In view of operating the apparatus, maintenance of cleaning the inside of the vacuum chamber by periodically converting cleaning gas into plasma or replacing members with new ones is performed. However, an atmosphere of the processing environment is changed between a state of a so called initialization moment and a moment of operating the apparatus thereafter, and as a result, a processing state between substrates is not constant. When the lot of substrates is changed, even between an initial replacement time of the lot and a time when the number of processed sheets of substrates thereafter increases, the environment atmosphere is also changed to influence processing uniformity among the substrates.
Japanese Patent Application Laid-Open No. 2011-3712 discloses a technology of adjusting the parameters of a processing recipe by sequentially measuring a processing result of the substrate and feeding back the measurement result, and managing an update of a feed-back value by using an accumulation time of applying high-frequency power or an elapsed time after initialization of the apparatus. However, this technique needs an expensive measurement device and deterioration in a throughput based on a time required to measure the processing result is inevitable.
Japanese Patent Application Laid-Open No. 2011-9342 discloses a technology of operating a substrate processing apparatus of connecting a plurality of process modules (PMs) that perform plasma processing such as dry etching to the vicinity of a transfer module that transports a substrate in vacuum. According to Japanese Patent Application Laid-Open No. 2011-3712, when a control job (CJ) which is first activated in any PM does not have a process job (PJ) which is executable in a corresponding PM, the CJ first belongs to another CJ and execution of the PJ which is executable in the corresponding PM is permitted. As a result, an atmosphere within the corresponding PM is prevented from being significantly changed whenever the PJ is executed. However, Japanese Patent Application Laid-Open No. 2011-9342 does not disclose a technology of reducing the influence of the processing environment which is changed as the apparatus is actuated.